1. Changes of state

2. Can you name the three states?

4. Observing changes of state

5. What is happening?

6. Changes of state solid liquid gas freezing melting evaporation
condensation
sublimation
deposition
solid
liquid
gas

7. Properties of solids, liquids and gases
Particles are held very close together by strong bonds.
Will spread out to fill all the available space.
Take the shape of the container they are in.
Solids
Particles are close together but can move past each other.
Have a fixed volume but not a fixed shape.
Have a fixed shape and volume.
Gases
Particles move very fast in random directions.
Particles vibrate in fixed positions.
Can be compressed (squashed) easily.

8. Properties of solids, liquids and gases
Particles are held very close together by strong bonds.
Particles vibrate in fixed positions.
Have a fixed shape and volume.
Liquids
Particles are close together but can move past each other.
Have a fixed volume but not a fixed shape.
Take the shape of the container they are in.
Gases
Particles move very fast in random directions.
Will spread out to fill all the available space.
Can be compressed (squashed) easily.

9. Written activity
Some students were watching an ice cube in a beaker as it slowly melted.
They were wondering why it melts.
Task:
Draw a poster that explains why an ice cube melts when left out of the freezer.

10. Key words